Fetal gastric maturation in a rat model: gestational changes in glucose transporter–1, glucose transporter–4, and insulin-like growth factor–1 receptor expression

Objective: To investigate the relationship between histological maturation of the fetal rat stomach and gestational stage-dependent expression patterns of glucose transporter (GLUT)-1, GLUT-4, and IGF-1 receptor (IGF-1R). Methods: Fetal gastric tissues were collected between gestational days 15 and 21 from fetuses obtained from Swiss albino rats (Rattus norvegicus). Histological maturation, including glandular organization, mucosal fold development, and muscular layer differentiation, was evaluated via light microscopy. Expression patterns of GLUT-1, GLUT-4, and IGF-1R were assessed using immunohistochemistry with a semiquantitative scoring system. Results: Advancing gestation was associated with progressive histological maturation and stage-dependent changes in marker distribution. Glucose transporter-1 immunoreactivity was prominent in the epithelium during early gestation but became more restricted with maturation, with relatively higher immunoreactivity observed in the fundus compared to the pylorus. Glucose transporter-4 immunoreactivity was more prominent during later gestational stages and was predominantly localized to muscular compartments. In contrast, IGF-1R immunoreactivity was weak during early development and remained minimal at later gestational stages. Conclusions: The findings demonstrate spatiotemporal changes in GLUT-1, GLUT-4, and IGF-1R expression during fetal gastric development. These observations are consistent with known developmental patterns; however, they do not provide direct evidence of functional metabolic changes. Clinical Relevance: These findings provide baseline descriptive data on gastric development that may support future investigations of congenital gastric abnormalities in veterinary and comparative medicine.